1. Field of the Invention
The present invention relates to a stationary probe for an analyzer. In particular, the present invention relates to a desktop analyzer having a stationary probe for aspirating or dispensing a liquid.
2. Description of the Related Art
Desktop analyzers, particularly for veterinary use and point of care (POC) human use, are known in the art. For example, the Abaxis Vetscan™ and Hemagen Analyst™ are both desktop analyzers for veterinary use. The Vitros DT-60™ is a desktop analyzer manufactured by Ortho-Clinical Diagnostics Corp. Other known analyzers include those POC analyzers described in U.S. Pat. Nos. 5,968,329, 5,747,666, 5,980,830, and 5,787,015, all of which are incorporated by reference in their entireties. U.S. Pat. No. 4,965,049 also discloses a modular analyzer system. U.S. Pat. No. 5,983,734 discloses a modular automated diagnostic system. U.S. Patent Application Publication No. 2002/0098116 ('116 publication) describes a biochemical analysis system. U.S. Pat. No. 4,797,257 describes analyzers and their components that use slides as test elements. U.S. Pat. No. 5,314,825 discloses a chemical analyzer having a rotary cuvette holder and a pivoting probe. These publications are also incorporated by reference in their entireties.
Known diagnostic systems, such as those described above, have generally adequately addressed size issues but often at the expense of functionality, test menu, and productivity. Most known systems perform tests serially on a single patient sample, significantly limiting walk away time for the user to perform other work tasks. These analyzers usually employ a number of dedicated subsystems within the analyzer to perform discrete functions such as sample storage and positioning, reagent storage, and waste collection among others. In some cases, multiple analyzer systems are required to perform the variety of test menus needed in the lab, for example, separate systems to perform immuno rate or electrolyte assays.
In many known systems, whole blood samples must be prepared (e.g., diluted or centrifuged) prior to testing, further limiting the users productivity. Reagent formats can be individual test strips (e.g., such as dry-slide technology), which offer the most cost effective solution and test flexibility, or multiple test formats (e.g., such as the Abaxis Vetscan™ rotor), which limit selective assay testing, and, as a result, drive up test costs. Liquid systems may compromise analytical performance when dealing with patient sample background interference compared to analyzers that use a dry-slide format. However, there are some tests which are incompatible with dry formats and therefore must use wet or liquid formats.
There is a need for small, portable in vitro diagnostic systems that are capable of automatically performing a wide range of analysis, preferably for both human and animal health care providers, and provide the flexibility to execute a variety of operations on patient samples with a high degree of simplicity and cost effectiveness. There are a number of factors that drive the need for improved products including:
Cost Pressures—Lower cost testing solutions that more effectively utilize system reagents and operation.
Ease of Use—Users at the POC and veterinary labs are often less skilled than most technicians working in large lab operations and often perform a wide range of lab and office functions. Systems utilized in these labs must be simple to use but offer a high degree of functionality. Systems that are easy to use with little maintenance or preparation of both sample and instrument are advantageous.
Increased Test Menu Capability—Systems are needed that can perform a wide range of tests without compromising analytical performance due to test format limitations. Current systems penalize the user due to their inflexibility to accommodate individual and panel tests without additional reagent waste associated with pre-configured test formats (e.g., the Abaxis Vetscan™ rotor or the Hemagen Analyst™ Panels+test rotor).
Size—Lab space is often very limited and portability is often a factor allowing the analyzer to be used at the patient location.
In developing such systems that achieve the above factors, there is a need to minimize the number of moving parts to save on costs and minimize space requirements. Known analyzers often use moving probes (e.g., U.S. Pat. Nos. 4,965,049 and 6,013,528 and the '116 publication) to align the probe with the test element, such as a well or slide, in order to dispense or aspirate the fluid being analyzed or assayed. Moving probes can also be used to aspirate and dispense diluent, reagent, wash and reference fluids. In some instances, the probes must be aligned precisely with the target receptacle. This results in expensive and space consuming motors, transmissions and control systems.